A lithium-ion secondary battery is disclosed in, for example, JP 2008-218248 A. The publication mentions the density of a negative electrode mixture containing a carbon material. More specifically, the publication proposes a lithium-ion secondary battery in which the density of the negative electrode mixture containing a carbon material is from 1.4 g/cm3 to 1.7 g/cm3 and the amount of the negative electrode mixture coated on the negative electrode current collector is from 6 mg/cm2 to 8 mg/cm2. The publication states that such a configuration makes it possible to provide a lithium-ion secondary battery with improved load characteristics and improved input-output characteristics.